1. Field of the Invention
The present invention relates to a liquid crystal projector.
2. Description of the Prior Art
In a casing of a liquid crystal projector, there are provided a liquid crystal panel, a light source lamp for backlight arranged on a rear surface of the liquid crystal panel, a signal processing circuit, and a power supply circuit. A cooling fan for cooling the liquid crystal panel, the light source lamp for backlight, and so on is provided in the casing of the liquid crystal projector. Conventionally, the higher the number of revolutions of the cooling fan is, the more the cooling efficiency is improved. However, noise is increased.
An object of the present invention is to provide a liquid crystal projector capable of reducing noise produced by a cooling fan.
In a liquid crystal projector provided with one or a plurality of cooling fans, the liquid crystal projector according to the present invention is characterized by comprising a temperature sensor for sensing the internal temperature of the liquid crystal projector; and a driving control circuit for controlling the driving voltage of the cooling fan on the basis of the temperature sensed by the temperature sensor, the driving control circuit controlling the driving voltage of the cooling fan in proportion to the temperature sensed by the temperature sensor in a case where the temperature sensed by the temperature sensor is in a predetermined range.
It is preferable that a temperature sensor used for on-off control of a light source lamp for backlight is used as the temperature sensor.
When two types of fans, that is, a suction fan and an exhaust fan are provided as the cooling fan, the driving voltage controlled by the driving control circuit for the suction fan against the temperature sensed by the temperature sensor and the driving voltage controlled by the driving control circuit for the exhaust fan against the temperature sensed by the temperature sensor may differ from each other.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.